I quite like Weird Wars, and although D&D 3.5 isn't the best system in the world, it is well known and fairly simple.  The Weird Wars presented here has predominantly developed from my Andover Campaign.  The rules have been updated from 3.0 to 3.5, bugs have been gradually ironed out and the rules enhanced so that more class options are available.

System Downloads

FileDateNotes
Blood on the Rhine Errata
04/03/10
Also includes the missing medal table (which is wrong) and the collision table, showing mph
Character Sheet
--Standard Weird Wars 3 Page Sheet
Classes, Basic
28/11/12
Basic character classes for all three services, expanded and converted to d20 v3.5. Updated to police medals.
Classes, Requirements
04/03/10
A table of the requirements of the published prestige classes
Classes, Prestige
04/03/10
BotR & AK prestige classes converted to d20 3.5
Classes, MI20 Prestige
02/10/12
The MI20 Adept, Chaplain, Knight & Operative
Ranks & Medals
15/01/12
Expanded rules for ranks and medals
Difficulty Classes
18/01/11
DCs for common skills and tasks (Updated to 3.5)
Artillery & Vehicle Crib Sheet
20/07/12
A crib sheet for the rules on artillery and vehicle combat ... hopefully it'll speed things up!
House Rules
04/12/13
House rules for Dead Eye, Massive Damage, Marksman, Bennies & New Characters
New & Adj Skills
11/02/11
New & Adjusted Skills, Feats & Weird Feats
Magic
24/02/10
Adept & Chaplain spell lists converted to d20 3.5
Equipment
17/02/10
New & Adjusted Equipment, Pay and a Price List, including civvy stuff

Session Notes

CharacterUpdatedCampaignScenarioSessions
Cpl McKie (#1)
17/05/10
Andover11-5
Cpl McKie (#2)
13/06/10
Andover
25-7
Cpl McKie (#3)
13/11/10
Andover
38-13
L/Cpl McAdder
21/11/10
Andover
415
2nd Lt McKie (#4)
02/01/11
Andover
416
Sgt Arnold (#1)
21/06/11
Andover
529
Lt Smythe (#1)
12/08/12
Andover
634-37
Capt Smythe (#2)
25/09/12
Andover
738-42 & 45
Sgt Arnold (#2)
20/09/12
Andover
741-44