When introduced to several people at once in an informal situation, I’ve found that being obvious about your attempt to remember names works surprisingly well. Repeat all the names, going around the circle and including your own name, two or three times. Pointing is optional, but in the circles I travel in, perfectly acceptable in this context. Make sure you smile.

Repeating the names several times helps them stick, and sometimes if you can’t remember a particular person’s name, you can reconstruct it by picturing how everyone was standing when you met. Including yourself makes it a friendly joke that helps out the others in the circle, so they’re more likely to forgive the weirdness.