There are a few event scripts that offer repeat events, but they generally work on the principle of every nth day, week, or month.
I want to sell tickets for community theatres that may have shows on for say 3 or 4 weeks but may only be showing on a wednesday, friday and saturday night with a midday show on sunday.
There is a feature on a competition's site that allows clients to add dates as sort of custom fields, so they can set up their event then add as many dates as they want.
It then displays individual "buy ticket" buttons for each date. As similar to the layout below;
DT Register can handle this type of setup using custom fields. Especially with our conditional fields structure (that no other solution has), you can accomplish some pretty detailed registration structures.
By the way, the upcoming 2.7 has support for regular repeating events too.