Astonishing Spider-Man and Wolverine by Aaron and Kubert, where they both end up in the Cretaceous Era. Seeing Peter with a crazy beard was cool enough but so was the story. And speaking of the Legion of Superheroes, DNA's reboot Legion has a story line where half the team ends up in the past and is part of "current" DC Universe's Final Night crossover. Then after about a year (?) in publication time, both halves of the Legion team are reunited back in their timeline in the future.