What about a 10-day cooperative event?

Each Stack Exchange community can contribute its own special brand of expertise, say in a specially created (community).meta page linked into a meta.SE question. For example:

• The UX community can propose full mockups of 'the ideal SE page'.
• The English Language & Usage community can overhaul the standard FAQs.
• The Interpersonal Skills community can come up with a new FAQ with standard cut-and-paste comments on how to effectively communicate Stack Exchange values and norms.

Programmers have long had hackathons. Why not organize one for SE's 10th anniversary?

There will be no obligation for Stack Exchange management to adopt any of the suggestions, but it would be a fun time for the wider SE community to dream and to express their ideas and ideals.