I don't have favorites but I think anything with great pictures to get people interested in knitting something different or a step up from what they've been doing would be good. Maybe see what the library has and just take one or two each week. I've looked at some books that have all kinds of stitch patterns that I want to try. I'm getting my nerve up to try set-in sleeves in a top down, no seams sweater. Working with a knitting buddy IRL on something like that would be great. Maybe there will be something you'd all like to work on, socks or something.
I should never overestimate my basic arithmetic skills.