Configuring media players and codecs (MPCHC, LAV Filters, FFDShow, xy-vsfilter)
Ripping Blu-rays with BDInfo, AnyDVD-HD, and tsMuxer
Writing Avisynth scripts to process the video and then encode and mux with x264, neroaacenc, and mp4box
Processing and resampling images with ImageMagick and creating GIFs
Learning more about resampling algorithms and other digital signal processing relating topics
Listening to death metal, grindcore, powerviolence, crust, hardcore punk, and other forms of extreme music
Antialiasing two and three dimensional mandelbrot fractals for the purpose of testing various downsampling algorithms, likewise for using Source Filmmaker to generate aliased high resolution images for downsampling
Deinterlacing interlaced video sources with high quality deinterlacers
Composing music in score editors such as Guitar Pro 6
Creating levels for Source-based video games like Counter-Strike: Global Offensive in Hammer
Thinking of ways to improve the graphics of current video games
Making lists