This one is worth grabbing even if you don't have an immediate use.
To celebrate its 15th birthday CheckPoint Software is offering a 12 months subscription to the full Pro version of ZoneAlarm firewall. The offfer is for 24 hours only and starts at 6.00 A.M. PDT, on Tuesday the 18th of November 2008.
This is a great product; I use it myself on several PCs. As well as a top firewall and HIPS you also get a pretty decent anti-spyware scanner as well.
Download page: http://download.zonealarm.com/bin/free/sum/index.html (Live from 6.00 AM PDT, Nov 18)
Original reference: http://www.pcmag.com/article2/0,2817,2334774,00.asp