Electronically draw names for Secret Santa. Configurable - will even exclude people from being able to draw certain names, based on user-provided input (e.g., no drawing yourself or your spouse). Just need email addresses of attendees.
Right & Left Rudolph Game - passing game. my family has played this for the last two years. one year we used gift cards, the next everyone brought a $2 lottery ticket. ( Search online for free variations )