Ring-a-Ding-Ding!

 is a quest in Fallout: New Vegas.

Quick Walkthrough
OR OR OR OR
 * Speak to Swank at the reception desk when first entering Tops Casino. He'll assist the Courier in killing Benny if: First pass a series of 3 speech checks, or pass 2 speech checks and have the distinctive cigarette butts, his lighter, and the note from Novac in your inventory. He'll return all weapons if convinced of Benny's treachery.
 * Speak to Benny directly.
 * He'll ask the Courier to wait in a presidential suite, and then flee; his bodyguards will be waiting in an ambush at the suite. You don't have to actually go to the suite; promptly leaving the casino will trigger dialogue that finishes the quest.
 * Passing a speech check of 60 convinces him to go alone with the courier to the suite where he'll answer questions before attempting to make a deal with the Courier.
 * Using a female character with the Black Widow perk will grant addition dialogue choices that will convince Benny to go up to his suite alone with the Courier.
 * Confront Benny on the Main Floor, and turn the whole Casino hostile. Having the Terrifying Presence Perk will grant a new dialog."I dug myself out of that grave to plant you in yours,Benny(attack)".
 * Speak to Yes Man in the suite (13th floor behind the double doors) to find out Benny's plan and the significance of the Platinum chip.
 * Once the player has gathered the necessary information, leave the Tops.
 * NCR and Caesar's Legion will be neutral toward the player after this quest regardless of any past crimes committed. Representatives from both factions will approach the player with requests from their respective chiefs to parlay.
 * The Courier can enter the secret back escape elevator off of Benny's room behind Yes Man without a key or using console commands. To do so, enter the The Tops and open fire on everything. Kill everyone on the first floor and grab Benny's suite key. Proceed straight to 13th floor to Benny's room, around Yes Man, and to the door to the elevator down the hallway. It will now mysteriously open to the subbasement. In there you'll find full metal armour in a locker, cases of random explosives, and 1 stimpack.

Detailed Walkthrough
Now that you know Benny is at the Tops casino in New Vegas, it's time to go find him. You can deal with Benny in a few ways:

I. If you speak with Swank, you can convince him that Benny needs to be taken care of (Speech 45). He'll give you Benny's Suite Key and return all weapons secured when you enter the casino. Find Yes Man in Benny's Suite and return to Swank. If you choose to take Benny out, Swank will send Benny to his room alone, where you can talk with him and also choose to kill him. This won't cause the casino to become hostile to you. There are other dialog options with Swank besides Benny needing to be taken care of, and other options like working with Benny when you talk with him. Note: Killing Benny in his suite, regardless of circumstances will not cause the casino main floor to become hostile to you (tested four times on XBox 360). Additional Note: Also, after convincing Swank of Benny's treachery, receiving your weapons back, and examining Benny's Suite, you can take a [Hidden], silenced sniper shot at Benny from behind the front desk. His guards were not alerted, nor were any casino patrons or staff. Even after speaking to his bodyguards and looting his body, no one became hostile.

II. If you speak to Benny and choose the peaceful resolution options: No guards will come after Benny's been killed and casino will not turn against you; four guards will come if you forgive him and let him escape. Note: When he was set free he takes off and he hasn't been seen since, so not sure where he goes exactly.
 * He will give you the key to the Presidential Suite and promptly send four bodyguards to kill you, fleeing the Tops Casino to The Fort.
 * If you pass the speech check of 60 to get Benny accompany you up to the presidential suite he will make you an offer. You can accept, kill him, or forgive him and let him escape.
 * If you have the Black Widow perk, it is possible to have Benny wait for you at the suite, where you can either kill him then, sleep with him then kill him in his sleep, or sleep with him and then fall asleep. If you sleep with him and fall asleep he will be gone in the morning and will have left you a note.
 * Benny will then be captured by Caesar's Legion. You will see him at the Fort and Caesar will give you the choice to decide how he dies or you can decide to help him escape. You only have two choices for his death; the first is crucifixion, and the second is battle him in the arena in a fair fight. If you decide to help him escape you will either have to kill all the Legion in the Fort, or give him a stealthboy and a bobby pin to help him escape. You must have a high sneak skill and a stealthboy for yourself or the Legion will become hostile. You can ask him what he will do if you set him free and he tells you that it's your choice; he can either take over the strip at your side or he will walk off into the sunset and never see you again. However it doesn't give you a choice to pick one or the other after that dialogue; you can only kill him or set him free. Caesar will also give you the platinum chip and he will ask you to destroy everything mister house has made. After that you can leave the fort but only without the platinum chip. Or you could try to steal you weapons back and try to escape somehow.

III. If you choose to confront Benny on the main floor of the casino, it will turn the whole casino against you.

Speak to Yes Man/Swank to conclude the quest.

Remarks on I and II After talking to Yes Man, you can speak with Swank and choose to take Benny out. The courier will need to head straight to Benny on the main floor of the casino. He may be on his way to his suite, but you may still be able to speak with him. If you want to gain a few extra caps before killing him, choose the Barter check of 35 and you can get 500 caps and 250 casino's chips. He will ask you to go to the presidential suite. After the dialogue, you can kill him immediately without making the casino turning hostile to you. If you are lucky and his guards are far away, his guards may not turn hostile either.

Outcomes:

I. If Benny was killed, Swank becomes the new boss and the platinum chip is recovered.

II. If Benny escapes with the chip, he will later be caught by the Legion.

You always get the Presidential Suite Key, either during the quest/found it on Benny's corpse.

After speaking with Yes Man, you will have another option for New Vegas, opening up the Wild Card series of quests.

Bugs
If you choose to wait for Benny in the presidential suite, nothing may happen after going up to the Presidential Suite. What should happen is a call from Benny at the intercom stating: "Baby, this meet and greet of ours? Chalk me up for a no show," followed by a short dialog and an ambush by four of the Top's bodyguards. The ambush may never happen. Instead, walking towards the elevator triggers a message from Benny: "The cleaners will knock twice. Make sure they're thorough." This allows further dialogue, but the ambush may never have happened. Choosing the dialog option "Lets make a deal" while in the Presidential Suite causes Benny to reward the PC (Player's Character) with 250 caps. If further dialog with Benny is chosen, he will reward the PC with a key to the "Top's Suite." If you talk to Benny in his room and choose the option "Player says goodbye" he will give you 250 tops chips. This can be repeated as many times as the player wishes. The player may choose to have both a violent and peaceful resolution to this quest, causing Benny to rise from the dead. First, present evidence to Swank so that he will give you access to Benny's Suite. After that, find Yes Man in the suite. Then go downstairs and talk to Benny in the casino, and agree to meet him in the Presidential Suite. (If desired, pass the Barter check to get 500 caps.) Then go back and tell Swank about Yes Man, and choose the option to take Benny out. Benny will then be alone in his suite. If the player talks to him, he will offer to comp you the Presidential Suite a second time and give you another key. If the player talks to him again immediately afterward, he'll answer your questions. (Some of the answers will result in Benny comping you the Presidential Suite multiple times, giving you another key each time.) The player may now choose to kill Benny. If they do, talking to Swank downstairs confirms his death ("Guess I'm in charge now. Ring-a-Ding.") However, if the player now goes into the Presidential Suite and uses the intercom, Benny will give his "No show" message and gives his usual talk with the player for a little bit before sending in the bodyguards. After surviving the ambush, talking to Swank seems to confirm that Benny got away. ("So now Benny left, and I'm the one holding the bag.")

Behind the scenes
The title of the quest is a reference to Frank Sinatra's 1961 song Ring-a-Ding-Ding.