I got to press the button...
I was a little kid barely knee high to a grasshopper & was part of a tour of a computer lab. The Big Scary Man in the puffy trousers (what the grey bearded old goat looked like to me) asked me if I wanted to learn to type my name on the keyboard. I said yes, stepped up, & carefully typed in "m y n a m e". He laughed, told me I was a fun kid, & told me to hit the enter key. So I pressed enter.
At which point the PSU caught fire & shot flames out the back like a flamethrower.
Best. Tour. Ever.
We were ushered out as quickly as possible while TBSM ran for a fire extinguisher. I've been in love with computers ever since. =-D