While the U.S. Army and Marine Corps provide their troops with a large number of explosive devices to use in combat, this does not stop the grunts from inventing more of their own. Iraq has seen the development and use of the;

Eight Ball -Take one-eighth stick of C-4 plastic explosive, add a detonator. Use it to gain rapid access to what's behind locked doors. This explosive device is sufficient to knock down most doors, but weak enough that troops can be close, and there wont be a lot of additional damage.

House Guest (one of many names)- A full tank of propane, with some C-4 plastic explosive attached to detonate it, will bring down most Iraqi houses when placed in the central hallway. The propane acts like a fuel-air explosive. This explosive was used when you had a house full of hostiles who would not surrender, and there was no artillery or smart bombs available to do the deed. Actually preferable to artillery or smart bombs, because there is less damage to nearby structures.

Super Incendiary Take one 60mm or 81mm white phosphorous mortar shell, wrapped three times with detonation cord and attach a quarter or half a stick of C-4 explosive. Set this off inside a building full of stubborn enemy troops, and the building will quickly burn down. Gives enemy troops an opportunity to come out and surrender. 

Modern Molotov Cocktail- Fill a container with one part liquid laundry detergent and two parts gasoline (or similar fuel). Instant napalm and excellent for burning stubborn enemy out of their hiding places. 

Troops have also improvised other explosive concoctions using left over Iraqi munitions, a practice that was very common during last Novembers battle for Fallujah.