There're plenty of e-card services around, but most limit the occasions you can choose from (birthday, anniversary, etc) and the sentiments you can express (happiness, sympathy, ass-covering masquerading as regret). Send something straight from your twisted heart, with Wrongcards
Dishing a different spin on e-greetings, Wrong offers free cards for a plentiful helping of events, all rocking a decidedly bent tone (don't underestimate the importance of not being earnest). Category-wise, Wrong starts with your basics, but executes them with refreshingly disparate humor, from bizarre (apology: "Sorry I found a dead bat and nailed it to your door"), to brutally straightforward (baby card: "You are so frickin' not ready for this s**t"), to happily dark ("get well soon -- because I'm not going back to jail for Necrophilia"). Category outliers include Workplace, Scientology, and Reminder cards (old-timey-looking jobs telling young ladies things like "you are not allowed to be remarkable"), as well as Thinking of You and Flirting -- helping you express what you're dying to say in person, but can't even bring yourself to drunkenly IM
Outlying even the outliers're the In The Event of Zombies cards, which dispense wisdom like "Always Yell 'Die You Godless Sons-of-Bitches!'" -- itself a limitation, because there's a little part of you that's secretly pulling for those brain-crazy freaks.