So the best case scenario is that it performs like Avatar, which parlayed a $3.5 million midnight gross into a $80 million opening weekend (4.5% midnight). The worst case scenario is that it ends up as frontloaded as a Harry Potter sequel (either due to its niche audience or the fact that it's terrible). New Moon and Harry Potter and the Deathly Hallows Part I both grossed around 18-19% of their weekend take in midnight screenings. A similar result (18%) would give Tron: Legacy a craptastic opening weekend of just $19 million. I'm personally thinking that it plays like a slightly front-loaded sci-fi entry as well as one somewhat more tailored to midnight audiences. So let's be optimistic, give it a 7.5% midnight take and guess $46 million for now. We'll of course know the opening day totals in about eight hours, so this is all purely speculation.