This format is terrible for working with line-based tools; you need to go an unknown number of lines back to get the date or the time. Although, TBH, the OP's

This format is terrible for working with line-based tools; you need to go an unknown number of lines back to get the date or the time. Although, TBH, the OP's suggestion of one-line-per-day puts too many items on the same ling. I would have gone with one line per event. Yes, there's more repetition, but you need no out-of-line context, you have to do a lot less parsing, and you can look at a fixed number of _columns_ and get the beginning of the description of each event, which is nicer for manual searching.