There is a ridiculous number of clubs at Haverford. Haverford has clubs for affinity groups (religious organizations, political networks, ethnic groups, women's groups, the Sexuality and Gender Alliance, etc), sports, dance, improve theatre, and music. There are so many options that you probably won't have time to do everything you want, but it's nice to know it's there. For example, if you want to try singing a cappella, you can join one of the eight groups on campus. Think about it. There are only 1,200 students on campus and still there are eight a cappella groups. Nearly 10% of Haverford sings a cappella! Crazy!
In terms of sports, leave your football helmet at home. We've been undefeated (i.e. without football) since 1972. Baseball, basketball, cross country, cricket (the only collegiate varsity team in the U.S., by the way), fencing, lacrosse, softball, soccer, squash, tennis, track and field, and volleyball are the varsity sports. Club sports include crew, golf, rugby, and ultimate frisbee.
On the weekends there are parties as well as other, non-alcoholic events. Fords Against Boredom (FAB) is a group that works hard to organize events like trips to see plays in Philly, quizzo, and campus-wide games like a photo scavenger hunt and water tag (otherwise known as "Assasin"). There's a dance about once a month, as well as some kind of musical performance every weekend. Late night food is available at the Coop or Lunt Basement. There is also a 24 hour Wawa within walking distance.
There are no fraternities or sororities. The dating scene is also notoriously lacking, probably because there are so few people. I know Fords in relationships, but it is not as common as at other colleges and universities.
Philadelphia is a short SEPTA (regional railway) ride away, so there are always things to do there. Common attractions include the Philadelphia Museum of Art, South Street, and various cheesesteak places.