My first hello world in a ZX81 (1985)

10 For N 1 to 100
20 Print "Hello World!";
30 Next N

Run 10

Mount my own BBS 
The Fidonet Groups
My first email account using QWK messages and UUDP
My Newton MessagePad
Install OS/2 v2.0 and 2.1
Windows NT 3.1 beta
My Thinkpad 701c butterfly
DOOM
My QuickTake 200