There are a number of factors here that determine how many computers can use a wireless router.
How is your DHCP set up? You will only be able to distribute the number of IP addresses the server has been set up for, so check that range. You can add fixed addresses on the fly, but that would ruin your party.
If your friends are doing downloads, that will soon clig it up, or trasferring large files back and forth.
Most wireless manufacturers recommend 20-30 users as optimum on a wireless router.
Be aware that although there are computers on the wired segment of the router, it is still affecting the performance of the router as a whole.
Recommendations:
1. Disconnect all unnecessary computers before starting.
2. Set out some basic ground rules, ie. no bittorrent downloads.
3. have the stats page of your router up on one of the computers (lock the screen) in case you have problems.
4. Enjoy the party.
Snibborg
