[thousandautumns]

In addition to many of the other great answers here, I would say cleaning your room/house and rearranging the furniture. One of the best things I've found for combating depression is changing my environment. Usually that means getting outside, but the reality is that life keeps most of us inside and at our homes for a non-trivial amount of time. Rearranging the furniture makes your home environment feel new and fresh. Its the first thing I try if I feel depressed.