Finish a project. I'm so guilty of having many projects in progress, but very few completed. Right now I'm working on tons of new costumes at once. It would be refreshing to actually finish one!
Practice finding your inner peace. Meditation is so beneficial for mental health and stress relief, but it can seem difficult to fit it into an already-packed schedule. Luckily, there are apps, YouTube videos, CDs and mp3s... all kinds of resources available to make your practice as easy as possible! I just downloaded this app called HeadSpace that has 10-minute guided meditations. (The first 10 are free!)
Learn the language of flowers. Okay, so maybe the secret meanings of flowers are completely inconsistent, but it's still fun to me! Why not read up on the meanings that others have assigned flowers (or make up your own) and gift yourself a bouquet or buy an accessory with your flower of choice?
Make a list of at least 10 things you like about yourself. Bonus challenge: make sure they have nothing to do with your appearance. Harper's list of 100 (!) is so inspiring. This is a surefire way to boost your mood, too.