Staying on the office theme: It's not cool to solicit donations or sales at work.
No, you can not ask for contributions for a charity (even if the company as a whole is supporting it or doing some sort of Christmastime project), and tread lightly before asking co-workers to buy your little darling Susie's Girl Scout cookies.
Here's why: soliciting funds from co-workers, no matter how good your intentions, puts the co-worker in an awkward spot, and essentially in a lose-lose situation. Here's what's going through coworker's head: "Geez, I don't really want to support Mitt Romney. But Dave's my boss. Can't say no to the boss."
Or: "Ugh, I don't need an 80th box of Thin Mints. And I'm having trouble paying my gas bill this month. But I don't want Sara to be mad at me. Okay, $4, I'll fork it over. Now I resent her."
Also, when it comes to soliciting funds for political or even charitable causes, depending on the circumstances, you're likely crossing some ethical lines.
Here's what is okay: You have a form/catalog/whatever. You discreetly, or perhaps in a short email (sent only using bcc!) inform a handful of coworkers, "Susie's got Girl Scout cookies. I've got the form. Stop by my desk if you're interested. Thanks."
The political donations, though? Keep those out of the workplace, period. In Business Etiquette, we talk about the four things you never discuss in a business situation: Religion, Politics, Money, and S-E-X.