I created a monster!!!!!...Me so sorry.
Your mother was a hamster, and your father smelt of elderberries!
You snotty faced wiper of other peoples bottoms! Now go ayway before I taunt youha a second tiemh! 
Dr Tanaka 50 Stone/Stone Tank
Cool MacCool 50 AR/Ice Blaster
Cold MacCool 50 ice/ice Blaster
Alura Darkstone 41 Brute Dark/Stone
Dr Akanat 40 Brute Stone/Stone
and many more
So, seems this could use a quick cut-paste reply. See if this is missing anything:
So, you want to know when Double XP weekend is?
Quick reply:
For 2009 (as I'm writing this, end of June,) we did not get a calendar like we did for 2008. We do not know when, or if, any are planned for this year until we get an actual announcement. To see if we've had an announcement, check the Community Digest and Dev Digest threads over in the Developer's Corner.
.Double XP FAQ
1. What is Double XP?
It's typically a weekend (Fri-Sun) where all XP awards are doubled. See the Wiki article for more information.
2. Why Double XP?
There are a few reasons:
<ul type="square">[*]Publicity
People like Double XP - even if they get 1.5x XP with Patrol XP. Double XP doesn't get used up over the weekend. (Neither does patrol XP - it's essentially on hold, though you can lose it if you get debt, as debt is 'paid off' with Patrol XP to begin with.) If there's not an issue or an event for a while, it's possible they'll use Double XP weekend as an 'event.'
[*]Testing server load
People renew, or take time off of work, for Double XP weekends. Why? Fast leveling, and lots of folks around - which obviously puts more of a load on the servers. I, personally, don't buy this as a reason 80% of the time, but it's useful for it anyway.
[*]There's nothing else going on right then
As mentioned - it's there to keep peoples interest and attention on this game, instead of letting them play Subscription Roulette (play for a month, go to another game for a month, then another, then come back here for an issue or event.) Keeping people here and active is a *good* thing for a subscription based game like an MMO.
[/list]
3. How often is Double XP weekend?
Rule of thumb is "roughly every six months," but that is not a set in stone schedule or dev promise, just an observation from players. Copying a little info from a post from Neuronia:
[ QUOTE ]
I took the time to look up the last 2XP weekends in Wiki, because the poster's question, while somewhat redundant, did have some legitimacy.
Double XP Weekends
21 July 2006 - 23 July 2006
26 January 2007- 28 January 2007
15 June 2007 - 17 June 2007
8 February 2008 - 10 February 2008
18 July 2008 - 20 July 2008
23 January 2009 - 25 January 2009
Generally the trend was to have one early in the year and one in the middle of the year.
There may be something fighting against that this year though. The massive multi-levelling brouhaha of Mission Architect, Issue 15 being launched "soon" and just generally faster levelling speeds altogether.
[/ QUOTE ]
4. When should I not expect Double XP weekend?
Looking at the list above, there are times that you probably shouldn't expect a double XP weekend. Has a new issue been released? They may have a reactivation weekend - but they probably won't want you to speed through the content at double XP speeds. De we have events? Note the list - none took place from October-December. We've got the Halloween and Winter events, though 2xp has taken place in January-February (a bit before the generally-valentines-themed Spring event.)
Not saying they WON'T happen, just that I tend to not expect them to at those times.
Mostly unrelated item!
For this and pretty much any question on the game, check the Paragon Wiki first! Head to search and type in what seems most likely or common to bring up an answer - Double XP, for instance, brings up a link to Double XP Weekends. And don't forget to search the boards!
Dang Bill, you have one for Double XP Weekend too!
*copies/pastes to Yahoo notepad*
Wouldn't want it disappearing when the forums migration hits. 
[ QUOTE ]
Dang Bill, you have one for Double XP Weekend too!
[/ QUOTE ]
Actually, JUST made that... thus the "Look like it's missing anything?" and the quote from Neuronia's post.
[ QUOTE ]
Oooh! Can I fly off the handle and insult someone too? Seems to be what all the cool kids are doing.
I'm accepting volunteers!
[/ QUOTE ]
You can go off on me. I don't mind.