Naughty nightwear (Fallout 3)

Naughty nightwear is a set of leopard skin pajamas found during the unmarked quest Grady's Package in Fallout 3 and at Mick & Ralph's in Fallout: New Vegas.

The outfit can be repaired using various "pre-War" and merc outfits including pre-War hats.

Unmarked quest: Grady's package
A humorous side quest (actually a sub-plot to the Nuka-Cola Challenge) involving the naughty nightwear can be found in Marigold Metro Station, which is near Grayditch.

Fallout: New Vegas
The naughty nightwear is identical to the version in Fallout 3. It can be purchased only from Mick at Mick & Ralph's in Freeside. It can be found in his "special" stock, which you can access to with a Speech check of 30. Alternatively, you can simply steal it through the bars of the shop's special stock. It is one of the few pieces of clothing in the whole game that can raise your Luck, the other being the Lucky Shades.

Bugs

 * The naughty nightwear's world model is bugged; when dropped, it looks identical to the sexy sleepwear. The all-nighter nightwear, however, displays an accurate world model, leopard-skin and all. It also shows on the clothing "nightware".
 * When you are accosted by Lug-Nut, if you drop the nightwear before talking to him, he still thinks you have it. Furthermore, if you "give" it to him, he'll spawn his own 100% condition copy before running off. Killing him will net you two copies of the nightwear.
 * When handing in the naughty nightwear to Ronald in Girdershade, if you managed to exploit the Lug-Nut "drop" bug previously, you cannot hand in the quest with two instances of the naughty nightwear on you. Simply drop one and then talk to Ronald to complete the quest.
 * Although the naughty nightwear does raise Luck and Speech, the increase in Luck is not reflected in any skills.