Update by Ros: The treasury trick can be achieved with relatively less loss if you are already constructing SH21. Speed up your build, and go on to Treasury 7. Do this during the solo 900k event (research and build). Even after you have achieved SH21, the kvk target remains the same (for SH20). I completed SH21 and Treasury 7 within the solo and the current kvk (5 x points for builds) and won 50k gold, plus a lot of speedups/items.
Update: This trick is ideal for the kvk event right before the kill event starts. A few people have tried this after the kill event, but have placed much lower in rankings because of bigs that are rebuilding their troop count.
With the current KVK at 6.9M points, it's an incredibly difficult challenge that requires an incredible amount of resources. However, there's a trick with the treasury that allows you to instantly complete this event, get a nice stash of gold and speeds ups, and even have a chance of making TWO leaderboards (both of which award even more gold).
If you haven't completed the last level of Treasury 7, it takes a lot of rss (AND gold to buy war bonds, about 80k), but has an amazing payout of 9.6M power for your overall building power. Since the KVK gives you one point per one point power for buildings, by completing this single building, you can instantly complete the KVK. The gold obtained from the KVK will just about pay for your treasury (which can give you 21k gold a month), and if you play your cards right, you can come out ahead in gold!
In order to maximize the benefit of all these points, amass a bit of silver (at least 40M), and complete the treasury during an inferno 1.92M research/building event. Do at least two large researches, and use the award of 18M silver from the inferno event to do another research(es) to get as many points as possible. You'll just about be guaranteed to make the leaderboard for both KVK and the hourly inferno event. If you win the Inferno leaderboard (not THAT hard with enough research and since there are so many of them), it's 35k extra gold. Joined with the 65K from completing KVK, you'll have more than paid back the 80k gold that you needed to complete the Treasury.
Cost of bonds: 14k gold for 1,000 bonds.
Total needed to take treasury to level 7: 4805 bonds (a little less than 80k gold needed)
P.S. I know I said I would post a casino trick, but the casino just changed today and so the trick no longer works. Avoid the casino for now.
Contributed by Taranis