It always annoyed me that Windows has no equivalent to the Unix "du -sk *", which will show the size of each item in a directory, with recursivly computed sizes for subdirectories. You can click "Properties" on each folder, but this is annoying and a waste of time. So because I wanted to learn how to use the Forms.NET package, I used this as an excuse to write my own.
This simple program prompts for a directory, then goes out and recursivly computes the size of each subdirectory, and shows all the results in a tree view sorted by size. Thats really all you can do with it, but I've found it useful when cleaning out folders full of junk.
I've provided the binary and the source in case anyone is interested, released under the GPL.
Binary plus source in zipped archive