You can type in a date in the lectionary date box, and it's pretty smart. It can decipher various date input formats (January 17, 2010; Jan 17; 1/17; all are smart enough to know that I mean the nearest January 17 to today).
But beyond that it's not very smart. These two issues should be fixed:
a) If you don't type in a date that is precisely a Sunday, it can't figure out the closest Sunday.
b) If you type in Jan, it doesn't propose in the dropdown all the possible dates in the upcoming January that fall on Sundays.
Also, please add a calendar input control (the kinds that is so common nowadays in software/websites where you have to pick a date; e.g. travel booking sites), so you could just click to choose the date, click forward/back arrow to go to next/prev month, etc.
