A tweekerroject is something a tweeker (someone on ice, or high-speed-chicken-feed) takes on at a moments notice. This is something that any normal sober person would never consider doing. Usually it means using a tool that is obviously wrong for the job, such as a detail sized paintbrush to paint a 10 foot wall.
Aye man, did you see Jimmy's tweekerproject. He was cleaning his engine motor with the tooth brush!