Definitely go to Fremont Street, like Happy Noodle Boy suggested. Be aware that it is a mile or so from the strip, so if you want to walk it like HNB then be sure to be drunk, like HNB. Also maybe don't do it at night, or don't walk away from LV Blvd if you do.

Definitely see Penn & Teller, even if you're not a big fan of magic.

Definitely go to Fatburger at 3am when they're blasting rap music and grilling burgers and having a good time in general.

Go to Ceasar's Forum Shops and look at all the things you probably can't afford.

Look at all the guys walking around with prostitutes and maybe consider getting one yourself (don't)

There's a bus service that I think is called the Deuce Bus, it goes from Fremont and all the way down the Strip with multiple stops. Walk the strip from beginning to end the first night you're there, then invest in a bus ticket so you don't need to bother doing that again.