You may already be familiar with Cards Against Humanity, the popular Mad Libs-style card game notorious for its politically incorrect humour. It's easy to get into, and success or failure always takes a back seat to simply having a good laugh. The makers of the game even offer the default set of cards for download as a PDF, to be printed off for free at home. However, like most party games, the main sticking point is often getting enough friends together at the right place and the right time. Pretend You're Xyzzy is the answer, when herding your desired humans across the city just isn't in the cards.
Pretend You're Xyzzy may be an unauthorized online clone of the physical card game, but it is completely faithful to the structure and content of the original. Most importantly, it is a powerful, browser-based way to organize games with friends and random strangers, according to rules and conditions set by you. You can literally enter the site and jump right into a match, in a matter of a few clicks.
There are a wealth of options available for you to set up your own game, be it a public free-for-all or a password-protected session for you and your mates. You set the scoring and time limits, number of players that may join, amount of allowed spectators, and even optional blank white cards for players to create their own custom responses. The site allows options for the inclusion of official expansion card packs, as well as favourite fan community creations (often with themes revolving around video games, anime, or other aspects of geek culture). Not sure what a particular pack includes? Browse the cards ahead of time, to see if it's for you.
Although there is a built-in chat window, with tabs for both your own game and for a global channel, if you're going to play with real-life friends your best bet is to agree on a voice chat solution ahead of time. Consider meeting on Skype or Steam chat before diving in, so you can all agree on how to set up the game and explain the mechanics to the newbies.
Nothing beats sitting around a table and sharing a game face-to-face, but for situations when that may not be an option it's nice to be able to set up something like this. Pretend You're Xyzzy is an ideal way to get in some quirky CAH action at a moment's notice, any time.