If you're reasonably petty or vindictive - and if not, why not? - it's likely you're holding on to an ancient grievance against at least one person. Before it leads to a Neapolitan-style bloodbath or crippling bedside guilt, why not aim to let the resentment float away? Yes, it may very well be easier said than done. But it's perhaps not a bad thing to aim for. Dwell on the positive, come up with an excuse for why this vile person did that vile thing, or do whatever other airy-fairiness it takes to get the job done.
Effort involved: none of the physical kind. Like Kegels, you can do them while just sitting there.
Image from: http://www.happyplace.com/10430/the-most-enjoyably-cantankerous-notes-ever-posted-in-the-workplace/
For Lent, which starts tomorrow, WaterAid has started a little something called Jars of Change. Basically, you order publicity materials and/or use the resources on the website to designate jars, into which members of your group plop the money they've saved by giving something up for Lent. Sworn off cocktails? That's $10 in the jar for each juice you have instead. The donations you collect will then go to fund safe water supply in Rwanda. WaterAid is marketing this appeal toward churches, but really, any group of people can take part.
Effort involved: if you're going to be abstaining during Lent anyway, you may as well motivate yourself and do a little substantive good at the same time. Deprivation will never have felt so good (to non-masochists, anyway).
Image from: http://fitvillains.tumblr.com/post/11529680010/fact-hydrated-people-are-sexier-than-non-hydrated
This is basically what it says on the tin. Upload a photo of your (living or dead) pet, for a chance to win a photo studio session or have your photo featured. Even though this isn't a lifestyle-shattering prize, the photos will be used in publicity related to the pet-spaying campaign. Pretty easy for a simple upload. Sadly, however, pregnant animals are not eligible.
Effort involved: you don't even need to take a fresh photo, just have a rummage around your folders.
Image from: http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=105x9656029
ZERO, which is somehow the abbreviation of The Project to End Prostate Cancer, is keen to attract advocates to spread information about the disease as well as push for policy reform. One of its activities in this regard is an annual conference, which this year will be held September 11-13 in Washington, D.C. Details are at http://zerocancer.org/get-involved/summit/. The webpage doesn't mention anything about pens and T-shirts emblazoned with the words "The Project to End Prostate Cancer" being offered to participants, but obviously these are reason enough to attend.
Effort involved: this is obviously a bit more labor-intensive than writing to a congressman, but this could be a good way to sharpen your campaigning skills, learn more about prostate cancer, and contribute to men's health in general.
Image from: http://gammasquad.uproxx.com/2011/07/xkcd-battles-cancer-with-science-comics
The human rights organization Womankind has an Overseas Aid Mythbuster in the form of an FAQ page. The information is UK-centric but contains some useful arguments for supporting development assistance. Hopefully by sharing this list with foreign aid skeptics you'll spark some debate, provoke some thought, verb some other nouns, etc.
Effort involved: a cheeky email?
Image from: http://nigel-sim.blogspot.com/2010/10/nigels-mythbuster-ep-2.html