ThinkPad laptops have a integrated light above the display, which provides light to the keyboard. Becaouse most geeks blind-type (without looking at the keys), and becouse the light (actually an LED) is orange in the R-series, it is pretty useless.
Pidgin notifications include blinking of the 'window bar' in the taskbar (which is easily overseen, especially with multi-desktop WM's), and an icon in the taskbar, which normally shows the status (available, away,...) but turns bright orange when there is a message waiting to be read. If you're watching a movie (fullscreen ofcourse) that has loud sounds, you can easily overhear the sounds and not-see the icons and blinking. That's why i decided to use the thinklight to help with the notifications.
When there is a a new unread message waiting, the LED is turned on, and when you read it, it turns back off.
For this to work, you have to enable IBM laptop extras in the kernel, to get the /proc/acpi/ibm folder, which contains thinkpad-specific devices, like the "light". I just wanted to test, so i didnt even try playing with fopen and writing and fclose, but just did the simple system("shell command");. Feel free to fix it if you wish.
The patch works with pidgin-2.5.8