Set Lasers for Fun

 is both a damage challenge and challenge perk in Fallout: New Vegas.

Challenge Requirements
Deal 16,000 damage with pistol grip energy weapons. The challenge description states you need to do the damage with laser pistols, but it can be done with plasma too.

Perk Effects
You're laser-crazy and it shows! Minor bonus to critically hit with all energy weapons.

Your critical hit chance with "All Energy Weapons" is increased by 2% (rank 1) or 4% (rank 2).

Behind the scenes

 * The name is a reference to the Star Trek line, "Set phasers to stun."