Of course it's possible...just not everyone knows how to do it. Some people don't seem to realize that college requires actual work and try to party all the time and then do miserably, while others don't realize that you need to give yourself a break every once in awhile. Depending on your major, you may have a lot of work to do at certain times. However, unless you really procrastinate, you should have time for a good social life as well.

Sleep...well that's another thing haha. Pick later classes if you tend to need to stay up late doing work.