Field Museum is great...best Chicago pizza, imho, is at Edwardo's [sic] at Dearborn, just north of Divison
running along Lake Shore Drive is a great run, if you're the active type
Rush/Division is an upscale bar/restaurant area where it's fun to people watch....Lincoln Park is a mid 20s-mid 30s hangout with plenty of great bars
Bucktown/Wicker Park has an artsy feel with some good small art galleries, unique eateries, etc. if you like the hippie vibe
best view of the city is from the Hancock Building - NOT the Sears Tower....but instead of paying for the observation deck, just head up to the Signature Lounge...you'll get the same view for the same amount of money, but at least you'll have a cocktail in your hand
Cubs are in town that weekend and Wrigley is a great ballpark
Greektown just west of the loop has some great restaurants if you're into Greek food
the REAL Little Italy is actually not too far from Greektown, just north of that...Grand Ave between Ogden and Ashland...there's a nice little Italian cafe that's reasonably priced on the corner of Grand and Noble, called Oggi...well worth it
other than that, tell me what you're into and happy to help...I miss living in Chicago