I'm buffered now, and grateful for it, but I spent several months budgeting biweekly. The way I thought of it was to forget about the Julian calendar when I budgeted because my budget period was two weeks, not a month or half a month.
My long term bills are categories which got enough per budget period to add up the the goal amount by the target date: A $200 payment due on November 1st would be $200/13=$15.38, rounded up to $16. I put that calculation in the note field next to the category name and I'm done.
Monthly bills depended on where I was. My last paycheck was on the 4th. Let's say I budgeted half of June's rent out of that paycheck, and the other half out of the paycheck on the 18th--and I can pay rent early! I do the same with my monthly car insurance premium and other bills that come out on the first. (My car loan and credit card payments come directly out of each paycheck, so they're easy to budget for). My student loan payment is on the 28th, and I budget around half out of each paycheck, which gives me some extra room out of some paychecks. You get the idea.
Let's say I'm hosting a big dinner party next month. I just calculate those expenses, break them out by category, and budget them as needed to get that amount. I'd probably do it in my entertainment category and add it to the usual category budget.
As Budget Ninja said, remember that anything left in a category just rolls over to the same category next month. Some people will choose to enter part of a paycheck to be "available next month" instead of "available this month," but I tend to just enter income as available in the month I plan to budget it so it will just be sitting there when I need to spend it.
"It’s still all about the method. Fancy Cloud Sync algorithm aside...the software is there to help you become more aware (Rule One), anticipatory (Rule Two), flexible (Rule Three), and secure."--Jesse's blog, A Method to Your Madness