Tommy has an incredibly hard, eight-stage multiball. I haven't even come close to completing it. You have to complete the first four stages, and then repeat all four stages with the blinders up. Here's a description of it that I copied from the rule sheet archive:
Stage 1
Jackpots: At the start of multiball, the left ramp is lit for Jackpot, and the right ramp for Double Jackpot. Initial jackpot value is 20M if you start at the Tommy hole, 15M if you start with the left scoop (or 40M and 30M for Double Jackpot). All playfield switches increase the Jackpot value by 200K, and the Double Jackpot value by 400K. Collecting any Jackpot launches an additional ball into play. When BOTH Jackpots are completed, both are relit.
Stage 2
3rd Jackpot. Collect either the single or double jackpot by shooting one of the ramps. Jackpots continue to rise by 200K/400K a switch, and the initial value is carried over from stage 1. After ONE of the two jackpots, an additional ball is launched into play, and you move on to the next stage.
Stage 3
Spell Tommy: The Tommy hole spots the letters T-O-M-M-Y and each one scores a 20M jackpot (which does not increase). No balls are added to play for collecting these jackpots. Completing TOMMY moves you to Stage 4. In 3.00 ROMs and later, each switch adds 1M to the Super Jackpot and 2M to the Double Super Jackpot.
Stage 4
Super Jackpots: The left ramp is lit for the super jackpot, and the left ramp is lit for the double super jackpot. The initial values are 250M and 500M respectively, and go up by 1M and 2M respectively for each playfield switch. You can only collect one of these two, so if you are going for the big points, avoid the temptation of shooting the much easier left ramp, and go for the right ramp. When you collect ONE of the super jackpots, you move to Stage 5.
Stage 5
Blind Multiball. You go back to stage 1 of the multiball, but the blinders are active, and you do not get any new balls added if you collect a jackpot. Initial jackpot values return to their base values. If you complete Stages 1 through 4 with the blinders active, then you must be Tommy, THE pinball wizard!