Half-Life Maps. There are some BSPs to be released, some RMFs needing a final compile.
Wolf3d (the real map, not the "inspired" one) needs double-check against the real gamemap. There is some tool to edit those - FloEdit II maybe?
...And then there are fragments of map ideas which might be interesting to smash into one super-massive nonsensical map to release all in one go.
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10/10/2014: Last year I polished everything up for a release for JustinCon 2013. There are two remaining items:
- dm_impact was undergoing a major facelift, and
- tfc_theft is incomplete.
Wrap those two and a release can be made.