I created a patch that allows us to skip Versioning and/or Timestamps when document is saved. (It's useful when you want to update certain attributes of the document but without creating a new version and/or timestamped updated_at attribute)
Instead of using Document.skip_callback class method, you can simply set #_skip_timestamps or #_skip_versioning to true, and the automatically defined callbacks (namely :set_updated_at before_save for Timestamps and :revise before_save for Versioning) will be skipped.
http://github.com/computadude/mongoid/commit/daa8350dd80c0a22c385c3f942b014b70a3bf3de
Example:
<pre><code>
get product record
p=Product.find '4c5325ade1b8325492000009'
skip timestamps:
p._skip_timestamps = true
update quantity
p.quantity = 2
save record:
p.save
p.updated_at did not change
</pre></code>