The Fun Mode mod is for version 1.4/1.5. The file is 1.2MB in size and the file name is FUNMODE.ZIP. It was released on December 4, 2008. There are two bat files included, one for playing with the eduke32 port and one for playing without it.
Quote from the text file:

"This is very FUN mod! Read list of changes:
1.Floor bullet holes.
2.Fixed explosions.
3.RPG explosion distribute shock wave.
4.Shrinker transformed to POOGUN! :)
5.Expander now transform enemys to... chickens!
6.Duke can eat shit! + 1 health!
7.Then troopers dies, they spawn small bonus taxi!
8.Then pigcops dies, they spawn small bonus pig tank!
9.Steroids give immortal to duke.
10.Health now 200.
11.Atomic health now 400.
12.You can save babes!
13.Freezer now shoot Laser.
14.Then you sit, you can poo. Just hit space.
15.Mod include new sounds, musics, con code and arts.
16.Changed voise of duke!
17.And there's a bit more too....he he he..."

This mod is funny and strange at the same time. I played the first two levels of episode 1 using it and it was interesting. It's definitely worth a try.

Download Here