Everything ends at the same time Marty
so if you're bidding on things you really want, best to open multiple tabs and then just concentrate on the couple that mean most to you.
At the stroke of 8pm no more bids will count, although your late bid will show on the thread, if the posting time was after 2000 it won't count.
Make sure you look in again on the listings later today and through the week as there's more itesm being added daily - I've got another load to go on tonight when I've finished my chores, so do keep an eye on the thread, not just your bidding items.