Spar Mile Challenge....6th and 7th of July.
I only heard about this last night at the Styker race. There are number of one mile runs which are sponsored by Spar, being run throughout the Country. The following events will take place in Cork...
Friday, July 6th at the Mardyke Track
Saturday, July 7th in Bandon Town Park, 1-5pm,
Saturday, July 7th at the CIT Track, 11-3pm
Saturday, July 7th in the Ballincollig Regional Park, 11-12pm

It would seem that there will be several runs at each event with people of the same standard running together. So, for example at the CIT track, those running sub 6 mins should start at 12 noon or 2pm. Those running between 6 and 7 minutes should start at 11:30 and 12:45 and so on. A full list of start times is available at the following website http://www.sparmilechallenge.com/event-timetable.php

It would seem as if you can register on the day.