Maintenance for the week of April 22:
• [COMPLETE] PC/Mac: NA and EU megaservers for patch maintenance – April 22, 4:00AM EDT (08:00 UTC) - 9:00AM EDT (13:00 UTC)
• Xbox: NA and EU megaservers for patch maintenance – April 24, 6:00AM EDT (10:00 UTC) - 12:00PM EDT (16:00 UTC)
• PlayStation®: NA and EU megaservers for patch maintenance – April 24, 6:00AM EDT (10:00 UTC) - 12:00PM EDT (16:00 UTC)
Yeah, you earn them by some activities during events. Collect ten (I think that's the carry cap), and you can buy a token from a vendor for that event. Combine multiple event tokens together and you'll get something.
This is all vague, because I don't think any of the real details have been announced yet. I guess, expect that stuff when Halloween rolls around this year.