Unadulterated: take something not meant for a gaming table and alter it for use on a game table. But the only alterations you can make are with paint. No drilling, attaching, modifying with bits. PAINT ONLY.
@Punktaku : make a dice rolling tower disguised as scenery for the game system of your choice
“Pop, pop, pop music"
Make a model inspired by music - it could be the physical embodiment of some lyrics, the band itself touring grungy underhive bars, or a lone minstrel trying to convince a party that "combat flute" is a valid and useful skill set to take dungeon crawling.
@Ben_S : Size doesn't matter.
Make something for any of our usual games (Necromunda, Mordheim, etc) that's either smaller or larger than usual for what it is.
@SuboptimusPrime : Beastmaster - Pets. A luxury to some, a weapon to others. Build and paint a warrior with a faithful fuzzy/scaly/silvery companion.
Build and paint something inspired by a work of fiction. A figure inspired by a fictional character, some terrain inspired by a fictional world or place, a diorama inspired by your favourite fictional moment, the whole of literature and cinema is at your finger tips.