Have extra Fortress sets lying around unused?
How about turning one into a fully functional Dice Tower?
Uses only a single FotA. Needs no glue, no tape, no knives or scissors, nothing else. Just the pieces that come in the box. Even the two angled ramps (the top hopper and the bottom deflector ramp) use no special equipment, struts, or glue to keep them in position. Ladders inside the tower serve as bumpers, ensuring the dice get a thorough tumbling.
This is version 2, which features an awesomely improved deflector ramp developed by ScrewDriver. It solves the two issues which plagued the first version: dice occasionally got caught behind the door hinge; and over time the deflector ramp would come apart. No longer. Props to him.
The seven-hex wallwalk piece with 8 battlements attached is the upper ramp (the hopper). The 2 single-hex wallwalk pieces joined together make up the lower (deflector) ramp.
The upper ramp (hopper) can be saved until last: it props up on top of the 4 battlements at the very top back corners. The lower (deflector) ramp, however, is best placed mid-way through construction: after you've built the bottom 4 levels, slip the two connected deflector tiles down the tower from above and wedge them in tightly at the bottom, tilted forward, so that their front edges are crammed against the inner walls of the doorway and their back edges are rammed against the four interior battlements. Then take the 'wooden' bar from the door, and drop it, on its end, into the small space just behind the door hinges, with the ring handle of the bar projecting forward into the corner. (See the photo below.) This will prevent dice from getting stuck behind the hinge.
Then proceed to build the rest of the tower, and crown with the upper ramp.
Don't forget the 4 battlements on level 4 (necessary so the deflector ramp wedges in at an angle), and the 10 ladder pieces inside the tower (which serve as bumpers for the dice, to ensure they get a thorough tumbling).
Note: 16 of the battlements on the front facade are used solely for cosmetic effect. If you don't like how they look — or just want to save your battlements for something else — leave them off.