Lots of apps on sale for Valentine's Day: Dungeon Defenders, Quarrel, more

Yes, it's Valentine's Day, but even if you're lonely and forlorn without love, there's good news: A bunch of iOS developers have put their apps on sale!

• The great Quarrel Deluxe is available for only 99 cents. Don't pass this one up if you haven't grabbed it yet -- it's a really quality word game with a lot of polish and great design.
• Dungeon Defenders: Second Wave is on sale for just a buck as well.
• Return7 is having a sale on the App Store, with both Debt Minder and Bill Minder on sale for up to 50% off.
• High end shooter Warm Gun is just $1.99 today.
• Hypership Out of Control is completely free today.
• Race of Champions is just a buck.
• Psychoban HD is also on sale for a dollar.
• The great 2D pirating adventure Plunderland is free for download.
• Dungeon Hunter Alliance for Mac is just 99 cents on the Mac App Store.
• Trainz for iPad is still on sale for 99 cents.
• BattleLand has gone free.
• iPad zombie shooter End Night has gone on sale for 99 cents.
• Interesting music title Frederic: Resurrection of Music is also just a buck.

So there's quite a few apps to keep you busy this evening, even if you don't happen to have a date to go out with.