Why not, you can add datepicker in your project of asp.net, In any WebForm inlcude all files given in demo of date picker, demos of jquery are available online on http://www.jqueryui.com.
Download jqueryui package and follow instruction given in demo. You have to use an ID in text box where you want to display datepicker and using this id, in javascript file you have to select and apply date picker like this,
$(function(){
$("#idOfTextbox").datepicker();
});