Bending cheap guitar effects pedals is a great way to start. More specifically these Arion pedals which can be purchased from Musicians friend and other online retailers for around $30. I would advise against Distortion pedals because those are too simple and contain no oscillator circuitry to play with. However chorus, octave, and delays are great. Most are built around the Bucket Brigade Delay ICs. Before deciding whether a particular pedal is worth bending check out the archives of schematics located on the super handy Experimentalists Anonymous website. There is just about every pedal schematic on there. Bentpedals.com also contains specific points of interest as well as some inside shots. Big thanks to Chris for sending in the inside wiring for the Bass Chorus and the Octave. Both of which contain enough points to require external break out boxes, massive rocker switches and joysticks.