Things to do during a Give it 100 (giveit100.com) "challenge."

• take up an instrument
• work on a language
• exercise
• learn to draw (combine with Learn to Draw in 30 Days book)
• work through exercises in The Artist's Way
• sew on a project
• read a book that you've not finished, but think you should (the Bible, encyclopedia, Moby Dick- whatever)
• teach child to drive
• clean/declutter the house
• practice yoga
• 100 days of kindness
• write
• come up with ideas
• learn to code (php, Ruby on Rails, java)
• improve handwriting/learn calligraphy

Many of these aren't amenable to video logging as recommended on the site, but the ideas are things where you should see big progress in100 days.