Best software to help run my lan party

Hey guys. I am hosting a large (100 person) LAN party in Nashville TN next month and was wondering what software we should choose to run at the event to help keep it running smoothly.
What do you guys use at your events and how do you set it up?
Any ideas?

Thanks.

For the network - we use PFSense (www.pfsense.org/) for the router software with HFSC traffic shaping configured.
For general LAN party use - we use ALP - www.nerdclub.net/alp/ . We run the server locally and use it for all tourney's and stuff like that at the actual event.