You can rename it depending on your preference. I prefer to have the date handy. . . . and as mentioned I rename my files on import. . . . so I don't generally name with the event as I often have more than one event that I'm importing. . .. that said, sometimes I will. . .. and sometimes I'll even create sub-folders for them. I.e. my July from last year has subfolders for the ballon races pics I took and pics DH took.
Really you could rename it to just about anything- you could include people, place, date, event, etc. Me personally, I find that the date comes in handy.