There are lots of things to do in Antarctica. People hike or ski to outlying places, sometimes to stay the night in huts. Watching and/or photographing wildlife and landscapes is always a popular option. You can go skiing, jogging or walking closer to stations.
If weather is bad, or you just feel like staying inside, then you can play volleyball or basketball, work up a sweat in the gym, play snooker or darts, watch movies or TV, listen to music, have a drink at the bar, surf the internet, send emails to friends, or read a book. In the middle of winter, those on station sometimes entertain each other with comic theatre and musical presentations.