ya I know what you mean by cliques..they started forming during my freshman year of uni..first quarter..then as I said I made new friends..like lots o_o cause they knew others and I got to know tons of people..and we formed our own little circle..but I mean we let new people in too so it's not like we're a clique..we're just really close..
i agree, college is definetly not as clique-y as high school. i hang out with different circles of friends, and once you know one, you end up knowing them all. so dont be shy about approaching people that are already with other friends, once one of them becomes a good acquaintence, they will invite you into their circle of friends and their activities.
another great way to meet people i find is to have
dinner/lunch on occasions.
my classmates always have an end of the year/after finals party where we do potluck at one of the classmate's house. or if it is your birthday, try using that as a way of inviting some friends/classmates to a small get together or casual dinner.
school activities is a category in itself: again, highly encourage it if possible
i'm actually only in one club at the school, and there are no such thing as sports or frats at our school either (uhh, its an art school, wut do you expect?) but the club i am in is called "Peer Health Advocates" and i get to meet a small group of students (there are about 12 of us?) that are interested in learning about student health. this is a nation wide club and you can get PHA certified since the club meetings act as small training sessions.
don't live in a dorm? know someone that lives in a dorm and go there often... hahaha... well, some of my friends did that

and it worked...
be friendly around school.enough said, some of my best friends from college i made friends with just by being friendly around school. one time i was waiting for an interview and this girl sitting outside was doing a fashion hw taking pictures with her camera, then it ran out of batteries so i offered her to use mine and then i email her the pix. since then we've become good friends and kept in touch. this other time i was visiting my friend at a different dorm and i was wearing an "everybody loves an asian girl" shirt, and one of the resident came up to me and said she had the same shirt too. then we kept seeing each other at school and always said hi. then we just started hanging out and partied together. now she's one of my best friends...

i'm trying to list as many examples as possible of meeting people/making good friends outside the classroom setting. it IS very much possible!