Here's a wide variety of 26 pair and trio activities
Most activities require a little student input, (5 - 10 minutes) so their preparation can be checked as homework. This forces students to come prepared, and homework grades are objective and transparent.
Each activity takes at least 20 minutes and if you speed date them, they can last for an hour or more.
With speed dating, everybody is speaking half the time, and half the time your partner is a better speaker. There's your language gain. Personally-relevant language gain.