Maybe it's the impending presidential election. Maybe it's the convention that's in town. There are numerous things that are reminding me of the power in numbers.
Lance Armstrong and Nike's Wear Yellow campaign is a nice example: pay $1, get a yellow bracelet in return and help raise $5 million for those living with cancer. Brilliant. $1 is a tiny amount to pay for anything, and you even get a little something to wear.
Another example that comes to mind is John Gruber's membership drive for his site, Daring Fireball: pay $30, get a cool t-shirt (I can confirm they are cool, as mine arrived yesterday) and help John to keep delivering great content. Pay a little, get something cool in return, help a good cause or fund something you enjoy.
These models work because of the power in numbers. Much like my somewhat unrealistic idea for generating power through exercise machines or a hand-crank that's installed in every home worldwide (crazy, yes).
This is merely a fleeting observation, and one that doesn't have a real purpose, other than to point out a cliché phrase: big things can happen, and are made easier, when people come together.