Here is an AppleScript that schedules the selected OmniFocus tasks for the coming weekend. If a weekend (as defined by you) is in progress, items will be scheduled for the current weekend.

In concept, the script really lets you to set start/due dates based on a relative weekly schedule. Simple modifications include:

• Changing your “weekend” to a different day/time range is as simple as modifying the settings at the top of the script. You could easily make a copy for “this week”, “next week”, “next Friday”, “next Thursday from 4:00-6:00”, etc.
• Un-commenting one line will bump it forward a week (think: “next weekend”).

Download it here