Want to know why your Linux box is sluggish? Some program is probably hogging disk I/O. I just discovered a cool utility that shows what programs are using the most disk I/O: [iotop](http://guichaz.free.fr/misc/). To install it on Fedora, run
yum install iotop
Otherwise, download and run [iotop.py](http://guichaz.free.fr/misc/iotop.py) — it requires Python 2.5+ and Linux kernel 2.6.20+