This year Memorial Day Weekend might be the busiest weekend of the year (4th July & Labor Day will be close). It will be the first holiday weekend of the 50th celebration, most of the rides (crossing fingers for Space Mountain) will be open, Buzz Lightyear's ride will be open (new rides = bigger crowds) and the weather is normally fantastic that time of year.
Put it all together, the numbers should rival some the highest for that weekend ever attained.