If you maintain an encumbrance record sheet, I will award an extra 50 XP per session.
For an example of the encumbrance sheet, check out the second page of the LotFP character sheet:
http://www.lotfp.com/RPG/uploads/pdf/CharacterSheetGrindhouse.pdf
The record sheet has several slots for you to write items in, and a few circles to calculate the encumbrance level, with the text of the relevant rules on the other side for easy reference.
I realize that some of you may not think tracking this stuff is fun, so I'm making it optional. However, I think it adds an important dimension to the game, and this particular system is really slick, so I would encourage you to try it.
So, a quick example: leather armor (+0), 10 items (+1) => 1, Unencumbered, no penalties.
Another example: high strength (-1), plate armor (+2), pike (oversized item, +1), 9 items (+1) => 3, Heavily Encumbered, penalties apply
If you are interested in the source, these rules are taken from the excellent Lamentations of the Flame Princess (LotFP) Weird Fantasy Role-Playing game:
http://www.lotfp.com/RPG/products/lotfp-weird-fantasy-role-playing
http://www.lotfp.com/RPG/uploads/downloads/GrindhouseRulesMagicFree.zip
The encumbrance rules can be found on pages 38 - 40 of the free rules book.
This game is basically a slightly mutated version of basic D&D. For example, it uses the traditional seven classes (cleric, dwarf, elf, fighter, halfling, magic-user, thief). It is one of the recent "retro-clones" made possible by the Open Game License that Wizards of the Coast used for D&D Third Edition.