Today is Dasara which is called Vijayadashami too. This means Victory over devilish things as on this day you may be knowing, Ram had killed Ravan the monster.

Apart from this on this day "Simollanghan" too is done, i.e. coming by crossing boundaries of town......may be it has relation with Pandawa...I dont remember exact story behind it. These days, it is not observed seriously esp. when boundaries of city are expanding. However, some ppl. go out to nearby places, exchange Apte pane as symbol of gold.

Then Dasara is counted auspicious that it is complete one day amongst three and half (sadetin muhurat)days which are supposed to be most auspicious in Hindus to do important things. So, ppl. do bhumipujan, vastushant, entry in new house or new purchases etc. on this day. New clothes, ornaments are purhcased or even start of any new venture is considered.

First auspicious day in the yr.is Gudipadwa which is in Chaitra (Marathi month) i.e.April, second day is Akshay Trutiya and third being Dasara (called somewhere as Dashahara too as it is 10th day of putting hara means flower mala on Godess Durga)and half day (actual full day but counted for half muhurat) is Diwali Balipratipada means Padwa.

Well, any correction and addl. info. in comment section is smilingly welcomed.