1.Login to blogger dashboard-->Layout > Page Elements
2.Click on 'Add a Gadget'.
3.Select 'HTML/Javascript' and add the code given below and click save.
<style type="text/css">
.month {
background-color:black;
font:bold 12px verdana;
color:white;
}
.daysofweek {
background-color:gray;
font:bold 12px verdana;
color:white;
}
.days {
font-size: 12px;
font-family:verdana;
color:black;
background-color: lightyellow;
padding: 2px;
}
.days #today{
font-weight: bold;
color: red;
}
</style>
<script type="text/javascript" src="http://dsai.588.googlepages.com/basiccalendar.js">
/***********************************************
* Basic Calendar-By Brian Gosselin at http://scriptasylum.com/bgaudiodr/
* Script featured on Dynamic Drive (http://www.dynamicdrive.com)
* Via http://bloggerstop.net
* This notice must stay intact for use
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/
</script>
<script type="text/javascript">
var todaydate=new Date()
var curmonth=todaydate.getMonth()+1 //get current month (1-12)
var curyear=todaydate.getFullYear() //get current year
document.write(buildCal(curmonth ,curyear, "main", "month", "daysofweek", "days", 1));
</script>
Now you are done.