Chicago and Las Vegas suggestions needed

[SOPi_Jawbreaker]

My brother is graduating from Purdue in May. The plan is for my dad and I to go to his commencement Friday night, and then the three of us will drive to Chicago to sightsee on Saturday. My brother's only been to Chicago twice, so he doesn't really know where to take us. I'm wondering if anyone has suggestions on what are the quintessential things to do in Chicago and also suggestions on really good places to eat that aren't too expensive.


Also, for Memorial Day weekend, one of my sisters and I are planning on going to Las Vegas. Does anybody have any suggestions on places to stay, shows to see, and places to eat?