xkcd - Updates M/W/F - Stick figure comic. Nerdy as hell, but you're on Neocities, so I figure you are too. Highly recommend.
SMBC - Updates weekdays - Fun comic, lots of single-panel jokes. Only slightly less nerdy than xkcd.
Homestuck/MSPA - No longer updates (completed) - Oh God, why is this on the list? Don't check this one out unless you think you're ready. Reading from the beginning *highly* recommended.
Questionable Content - Updates weekdays - Comedic slice-of-life. Questionable quality, but not Questionable in a spicy way. Honestly warrants a warning more than Homestuck does. Reading from the beginning recommended.
Nose Ears - Updates whenever - Silly little 3-panel comic right here on Neocities.
Dinosaur Comics - Updates M/W/F - Same art, different comics. Wonderful nonsense.
Awful Hospital - Updates whenever - High-concept, narrative-driven, body horror interactive fiction. I very much recommend this one to anyone who can stomach it.
UNDERTALE - $9.99 on Steam - You've probably heard of, if not played, UNDERTALE, but in case you haven't, I really do highly recommend it.
Hacknet - $9.99 on Steam - Hacking simulation game. Lots of open-ended puzzle fun, and a pretty cool story at that.
Ad Verbum - Free in browser! - Wordplay-heavy text adventure game. Short but sweet. Every puzzle will either make you feel clever or stupid.
Blackbox - Free with in-app purchases, no ads, iOS-only. - Tricky, transreal, abstract puzzle game. Really plays with out-of-the-box puzzle solving. As above, every puzzle will either make you feel clever or stupid.