Istanbul municipality is organizing a marathon each year. The marathon starts from Asian side and ends in European side of Istanbul. For the people who want to experience walking the bosphorus brigde there is a fun run section as well. You can join this event to walk together with other cs'ers.
The event is free and there is a madal and tshirt gift for the participants. Dont forget to register to event on booths located in many squares around Istanbul.
More info can be found on:
See you there!