Accepting that this really belongs in ASB's it is nonethess a good speculative question. If we assume intellegence in a mouse or squirrel-sized bipedal mammal is possible, there may be some interesting ecological and physical conditions to affect how their societies/technologies developed.
(1) Architectcure/settlements. Much smaller, lighter structures to support much smaller lighter creatures. Possible location of settlements/towns in trees to escape larger predators in early history and then continuation of this pattern as urbanization develops. Perhaps individual trees are political units, forests are like continents or islands, and treeless savannahs are like oceans (alternative is living in warrens and burrows, but this doesn't seem as cool to me)
(2) Agriculture. Given the size of the plants domesticated for human cereal and tuber agriculture, this would be more akin to forestry to our smart rats. Probably much less development of agiculture in our sense, except possibly for fungi. Wild god-given acorns have the economic/spititual significant grain breads do in ours.
(3) Animal husbandry. Iffy. All animals domesticated by humans are either deadly predators to these little guys or way too big to be domesticated. Maybe herds of turtles or guinea pigs. Or small birds. Also bugs, lots of bugs.
(4) Technology. Probably based primarily on using wood, clay, bone, feces, and grasses. It probably takes too much raw physical strength to chip stone tools or forge and hammer metals. Possible use of more pottery and chemical technologies (etching, crystal growing, etc). If fire is tamed, probably far less widely used than by big guys in stone house like us.
(5) Weapons. "hand" thrown projectile weapons would be a lot less useful, owing to the lightness of the projectile and air resistance (try throwing a 4-inch long match stick javelin at your cat 6 feet away and see if he even feels it). Tiny swords and daggers made of sharpened wood or bone would be good. Catapult-like devices would be necessary to impart valuable kenetic force to heavier projectiles like rocks or useful sharpened arrows. Acid, poison, or fire based weapons might be more common. Guns (of a sort) might actually occur earlier than in OTL.
(6) Travel and Transportation. Gliding and powered flight would probably occur much earlier, given the light weight and high metabolism of these little guys. It would take a lot less effort to have a "mouse" powered set of wings attached to their little selves, and given their light weight, even a long fall to the forest floor would usually not have fatal consequences (again try this with your pet gerbil if you want to be hitleresque!). Probably the only machine engines likely to evolve would be those based on enegry produced or conveyed by spring tension, gears and pulleys, twisted fibres, etc., as it takes metallurgy to make steam and combustion engines. Maybe animal power from bugs, turtles, birds and any other small domesticated animals.
This is just a start.