The Carnival of the Damned and Frozen in Time for me. In addition I was able to snag a copy of Doom of the Savage Kings on eBay for less than six bucks.
The Carnival of the Damned is a O-level third party funnel that seems phenomenal. The backstory alone has me hooked. This is one I'm going to run for DCC, but I think I might also use it to kick off a 5E game. I'll do a post solely devoted to this adventure soon.
Frozen in Time is a fun sci-fi/fantasy/caveman mash up. Set in the frozen north, the party tango with time-displaced creatures and robots. I have the second version, which is printed digest size (meaning the print is really tiny) and contains a bit more info about the frozen north. Another cool thing about this adventure is 0 level occupations for cavemen.
Finally Doom of the Savage Kings is just an absolutely solid 1st level mini-sandbox. Because of the the names and such it has a definite Beowulf/Old English feel to it.