In my first sparring class we had about 20 people show up, and the instructor had us spar for 90 seconds, then change partners, spar for 90 seconds, change partners, ect...
Every now and then he would have us do 20 pushups or jumping jacks between partners, then back at it.
We were sucking wind.
It was good because switching partners made me have to re-think my strategy on the fly. Even though 90 seconds is a short amount of time, 90 seconds takes a long time when you're sparring.
I did pretty well, and didn't feel intimidated. The higher ranking students that I sparred with pointed out some of my mistakes and took the time to give me pointers, so even though I got clipped a few times, it was a good experience for me.
Insert profound martial arts quotes or tough guy phrases here.