Sonata Arctica, Arsis, & Holy Grail North American Tour
This was just announced today for Toronto on December 11. I'd have to imagine it's a whole tour, but I didn't find any other dates.
12/5 - Phantom
12/17 - Havok
12/23 - TSO
1/13 - Enforcer, Warbringer, Cauldron, Exmortus
2/27 - Sacrifice
3/4 - Voivod, Vektor