Waste not, want not
A reinforcement for a wiring port (on my GT) made from an eyelet out of a worn-out Mavic Open Sport rim. There are two wiring ports on this frame – this one under the downtube up by the fork, and the other on the seattube right where the seatstays cross by on their way to the toptube (I reamed the top 6 inches of the seattube from 26.6mm to 27.2mm, and the seatstays cross about 7 inches down from the top of the seattube) so I can run wiring via the BB (and also run wiring out the chainstays if I want MOAR LIGHT!)