Enhanced RecentChanges (now default in MediaWiki core) group edits of Special:RecentChanges and Special:Watchlist by title and day, as opposed to "normal" RC which just lists all individual edits sorted by timestamp.
Sometimes it would be better to have an even more concise overview, grouping edits by week or even month. All edits for a page would show up as a single row. This is especially useful when some pages are much more frequently edited than others and hence occupy many more rows than others; it's also useful when a Watchlist/RC is rather quiet, as it allows to have links to combined diffs even for edits happened on different days.
Someone even made an extension that does something similar, it seems: http://education.wmflabs.org/w/index.php?title=Special:RecentActivityFeed&days=360&from=