BPM beat counter
Simple is beautiful! Who needs fragile BPM software when you can do the counting yourself!? Here's two online BPM (beats per minute) counters where you hit a key for each beat. The form will give you the average BPM.
For the mouse:
http://www.b-boys.com/classic/beatcounter.html
For the space bar:
http://web.forret.com/tools/bpm_count.asp
This also comes with a "tempo calculator" if you hit Submit.