This was definitely the game I liked best in Essen, and I think it would work quite well here.
It's pretty simple. There's a 5x5 grid of words and 2 teams of at least 2 people each (one team is blue, the other is red). Some of the words are (blue or red) agents, some are civilians, and one is the assassin. One player from each the team, the spymaster, gets to know which words are which, and in the game, he gives clues to the rest of his team to find the agents of that team's color. The first tean to identify all it's agents wins, but if a team guesses that the assassin is one of their agents, they immediately lose.
Giving clues works as follows: One spymaster starts and says a single word that is associated to as many agents of his own color, but not to any of the other words, especially not the assassin. He then says the number of agents of his own color belong to the word. Then the rest of his team guesses what these words are. They guess one word at a time, and the identity of the word is then revealed. If it was correct, they may guess again, for as most as many times as the number the spymaster said plus one. If they hit a civilian or an agent of the opposite color, or decide to stop guessing, it's now the other team's turn. If they hit the assassin, they lose immediately.
Full rules can be found here:
http://czechgames.com/files/rules/codenames-rules-en.pdfAnyone interested in playing? I think the ideal number of players would be 4, because if the guessing parts of the teams contain more than 1 person, they'd need to discuss their guesses, which could lead to long waiting timeson the forum.
UPDATE: You can now start games on your own without needing a moderator:
Kuildeous made a Google spreadsheet that allows you to easily create your own game without a moderator: https://docs.google.com/spreadsheets/d/1TXkY5snm_uhZQNYvGqwrLSHjuHARIZouOP5pBEWRMXA/edit#gid=0
One spymaster simply opens the sheet, waits for it to fully load (i.e the words don't start with BOOT, KEY,...), then copies the two messages in the bottom right and sends it to the appropriate places.