TripleByte gets plugged a lot on HN, but I think a lot of people still don't realize what a great time investment it is. I woke up early and did their 3-hour in

TripleByte gets plugged a lot on HN, but I think a lot of people still don't realize what a great time investment it is. I woke up early and did their 3-hour interview before going to work one day. Within a week I'd been offered 30+ on-site interviews at well-funded Bay Area startups, as well as a couple of bigger companies (Palantir, Stripe). Their interview was engaging and challenging and produced lots of useful feedback. You also get lots of chances to talk to the founders of companies (or sometimes employees for the bigger ones) and evaluate whether an on-site is worth your time. Especially valuable if you lack a big name on your resume and can't open doors that way.