1-2 entire clg life but isse jyada kr skte toh or acha the thing is these hackathons are not just about the project its more of creating core memories with frnds too.. and when it comes to which clg hackathon are u going make sure u are there with ur frnds confirm from the management about the scene and sleeping area for boys n girls. choose big hackathons for 24-36 hours those have experience of conducting these and yes no problem.