Here is my old rattiest of rat bikes, affectionally known as the 'Spice bike'.
-Frame/fork was found in a dumpster behind my work. Muddy fox 90/2000s. The paint flaked off by hand, rusted and pitted to the point the steel was delaminating around the seat tube. I stretched the rear triangle from 130-135. -Saddle and post came with it, couldn't adjust the height as it was rust-welded in place. -Bars and stem are off an old Wethepeople BMX -Drive side crank/chainring are FSA my mate gave me, the left had was a mismatched arm that was the right length. -Single brake, tektro I think, came on the bike. -Rear wheel I found in a forest while doing some 'proper' riding. -BB was probably the newest part, shimano cartridge out my dad's garage. -Running the derailer as a SS tensioner, barrel adjuster to change cogs if needed. -Tyre's were shot, the front blew a sidewall during a hill bomb and it nearly killed me. Replaced it with a Conti DH tyre that was hanging on a tree at our local trails.
Anyway this thing ripped as a commuter/pub bike. Felt weird with the tall bars but actually a comfy seated position. got a lot of weird looks. It finally died and I sent it back into the biffa bin it came from. Wish I had more pics!