Visiting Philadelphia, need a guide on what to do

Great recommendations so far. I'll add Rittenhouse Square and Love Park for great views, Old City especially on 2nd St b/w Market and Chestnut streets for bars/clubs, and check out uwishunu.com for upcoming events in the city.

Hello Svetlana!  You have some great recommendations below.  I also think a tour of Eastern State Penitentiary is really interesting.  

It really depends on what you like.Judging from your name you might enjoy visiting Bustleton Ave with it's Moldovan,Georgian ,Russian and Uzbek restaurants , clubs and stores.Then again that might be the last thing you want to do.Philadelphia is a city of great art museums-Philadelphia Museum of Art,Barnes Foundation and Pennsylvania Academy Of The Fine Arts.I enjoy Italian Market with it's food stalls.Want American history-Elfreth's Alley and Independence Hall.Like zoos Philadelphia Zoo is one of my favorites.For a concentration of clubs , bars and restaurants South St.Old industrial town area now restaurants, stores etc.-Manayunk.Want that college feel-University of Pennsylvania area.I used to vouch for a restaurant around there called White Dog Cafe.Enough ?

Visit the funky part of town by walking along South Street in South Philadelphia. Grab a steak sandwich at Geno's Steaksor Pat's King of Steaks across the street in South Philly. CHeck out City Hall area and the Pennsylvania Academy Of The Fine Arts on Broad Street. Also visit our world famous Philadelphia Museum of Art.

Tell you what you like to do at home, and where that is, and I can recommend plenty of things along those lines.  My wife and I keep a record of our favorite restaurants, dishes at restaurants, things to do that we've enjoyed.  Also how long are you staying and when during the week would be helpful. 

I would visit the Reading Terminal Market, Philly is known for the it's food so you don't wanna miss it!