Something my friend suggested about this that has worked wonders for our family too is this:
Box up ALL toys that are not age appropriate or played with often. Stick them in the attic. If they are still there un opened [and un asked for etc] after 6 mo, DONT open the box, just carry it to a donation location and count your blessings for having so much to give.
With the rest of the toys, divide them up into categories [make your own; we have books, videos, trucks, dolls, blocks, art, other] and take ONE toy from each category [max two] and put it out on a shelf or toy box or what ever. Put ALL of the rest into a [big] box in the closet, garage, wherever. Then once a week [or what ever time frame you chose; we do Sat morning] rotate thru the toys in the boxes and bring out 1-3 "new" toys and put away an equal amount of "old" toys. This helps keep them interesting and more readily used/loved.
Finally, when asked "where is such-n-such toy" just say "oh, new system, must be in the closet, etc". Or, brag to relatives about your new system, how cool it is, etc, and in the process mention how this way children dont get 100 new toys at christmas and nothing the rest of the year, but something "new" each week instead. Add a pitch for your categories while you are at it, and mention that there arent "violent" videos too [or what ever you chose etc]