Okay, crazy idea, not at all sure if it's actually even plausible, because most users are always late or leave their votes for the final day, but I'm going to try to set an example.
So our special TISC spinoff edition could be sports related not in the term of theme, but in the way that the songs compete.
Example: 36 songs in the competition are divided in six groups of six
in these groups, every single song faces each other.
Every user gets three points to distribute in every match, so the score can be 3:0 or 2:1 between the songs and they are all then tallied up to find out the winner of that specific match, points difference matters in case of ties.
Different users could even be in charge for different groups to share the workload.
Let's say that 3 songs from every group survive to form two groups of 9, the top 3 songs from Group A fight against B and C, the same for D, E, F and after that single round robin, 4 songs from each group advance and are seeded into the quarterfinals, semis and the final to find out the winner.
For quarters, semi's and finals I think everyone should get 5 points to distribute, to add in some variety, 5-0, 4-1, 3-2 would be the options.
PROBLEMS:
This would have to be run a bit similarly as a prediction contest, people would need to vote actively and more frequently than just that single time that you do for TISC
Multiple people running the show would mean more people have access to the results and that might be a worry in regards of fair play
No guarantee that with this system the best song wins