Electronics, vintage computers, video games
My vintage systems: Tandy 1000 HX, Tandy 1000 RSX, Tandy 1100FD, Tandy 64K CoCo 2, Commodore VIC-20, Hyundai Super16TE (XT clone), and some random Pentium in a Hewitt Rand chassis...
Some people keep a classic car in their garage. Some people keep vintage computers. The latter hobby is cheaper, and is less likely to lead to a fatal accident.