A standard, suped up game of TI, four hours (7PM-11PM)!?
We got us a comedian! In my experience, it takes about an hour just to get everything set up, organized, distributed, and all players and situated-- even with all the components separated and organized for distribution beforehand. That's with players who have some experience with the game and the group. Then the first couple rounds always seem to take a long time, especially with all the domain counter conflicts and delays which tend to crop up and make things interesting early. Maybe you could cut it down with one of the pre-made galaxy maps and pre-chosen factions. That's a maybe, and then you better hope that the top Stage II is the Rex and the frontrunner draws it with Bureaucracy. Then you want to take an inventory afterwards too?!-- Which I completely understand. Do you have a way of freezing the game that allows a group to come back to it later?
In my experience, the question "What are you doing today?" can be adequately answered with "Twilight Imperium".
According to people at the store I am quite a comedian, but I'm not kidding about the time limit. We've played multiple games where we started late having everyone situated by about 7:30pm and having everything cleaned up by 11:30pm. Turns go quite fast at our store as our experienced players have their turns planned ahead of time, sometimes full rounds in advanced, and the the only thing that really eats up the majority of time is combat. In our experience, we estimate total game time to be about 45 min - 1 hr per player, which includes the new players or the slower players. TI doesn't have to take all day to finish a full game of 6 so long as everyone is focused on objectives and avoiding pointless combat.
Our record game so far actually happened last week. 5 player game, 1 of them being completely new. We started the first strategy phase at around 7:30pm and every strategy phase the new player had to read at least half of the strategy cards. We taught him game basics and some advanced strategies AND finished the game by 10:15pm with me winning at 9 points. Cleanup was finished about 20 minutes after and I ended up bored for about an hour because I had all that time set aside for TI before work.
Our longer games were long mainly because 1 player attacked another for maybe an objective or used an action card that deters another player just to try to stall waiting for a specific strategy card to be used. Then the defending player (or victim) decides to turn that into an all out grudge match. Here's our most infamous example:
Player A reveals Industrious People or whatever the counter is that gives a free space dock. Player B, waiting for Production to be activated stalls for one turn by using Industrial Agent? as his action destroying the free space dock as it was the only valid target for the action card. Player B exclaims, "That's a declaration of war!" and Player B clearly explained that he was waiting for the activation of Production otherwise he loses a full round of invasions on his systems adjacent to his home system and apologized. Player A then began doing nothing but building large fleets in order to attempt an elimination of Player B and Player B was forced to do the same in order to defend himself. All combat during that game I believe was only between those 2, all the while the other 4 of us were focused on objectives and were able to accomplish scoring without firing a single shot at each other. Needless to say neither Player A nor Player B scored a single VP and we finished the game with the rest of us having scores between 6-10. At least 2 hours of game time could have been avoided if it wasn't for a personal grudge over something as trivial as a free space dock that was in a "good position" on the board.
Things that speed up TI:
Artifacts, Voice of the Council, Bureaucracy playing to 9, focusing on objectives, planning your turn ahead, organized pieces/cards/tiles. If possible I can try to take pictures of how my TI is organized and post them. One of the biggest things that also speeds up our games is that when we hear the words "building or producing or transfer action" we ask the next player, "is anything he's doing relevant to you?" if the response is "no" then we proceed with that player's turn. Same with combat. "Is their combat relevant to you?" "No?" "Will your turn have any effect on the result of their combat?" "No?" "Go ahead and take your turn."
Things that slow down TI:
Personal grudge matches, pointless combat, planning your turn AFTER you realize it's your turn, some dramatic change that changes the turn you just had planned.