cal=Calendar.instance
Y=cal.get(Calendar.YEAR)
M = cal.get(Calendar.MONTH) + 1
D = cal.get(Calendar.DATE)
println "$Y-$M-$D"
get beginning of a day
def now = new GregorianCalendar()
def today = new GregorianCalendar(now.get(Calendar.YEAR), now.get(Calendar.MONTH), now.get(Calendar.DAY_OF_MONTH))
date=today.getTime()
println date
http://jqueryui.com/demos/datepicker/#icon-trigger