mur'phon

Well, there's lots of stuff you can do over here. Depending on what kind of activity you prefer, you might want to visit some of these locations:

1) Sightseeing

- Kalemegdan fortress

- Knez Mihajlova street

- Trg Republike (eng. The Republic Square)

2) Sports/Activities (better suited for spring or summer, but still worth mentioning)

- Ada Ciganlija

3) Shopping/Malls

- Delta City

- Mercator

- Ušće shopping mall

- IDEA

The above are just off the top of my head. If you're into clubbing, music and drinks the number of places you could visit is too large to even think of giving examples. There's also a bunch of movie theaters, museums and parks. Hope this helps a little.