Several of them, from an old Mac mini to a new AMD 8-core monster!
Computers, mostly. I'm a geek from way back. Got my first calculator in 1976, and been hooked ever since. One other guy and myself were the first ones kicked out of HS computer class for 'hacking' (all we did was create a basic program that password protected our machines, the teachers machine and the mainframe, but it didn't work too well and blocked out everyone including the guy they had to call to fix it. It was down for a day and a half. After that, all students and parents had to sign a "no hacking" policy. This was in '83, BTW!)