Psensor is a graphical hardware temperature monitor for Linux. It can monitor temperatures of the different hardware sensors (motherboard and CPU using lm-sensors), hard disk drives (hddtemp/libatasmart), and ATI/Nvidia GPUs. The fan can also be monitored (lm-sensors). Psensor is designed to be simple and easy to use.
claws-mail-indicator is a simple plug-in which adds support to Claws Mail for the Ubuntu indicators. Notifications are displayed in the Messaging menu, with the option to display a notification bubble each time new messages arrive. It was developed and tested on Ubuntu 11.04 (Natty) 64-bit.