I also have a really stupid one when me and a bunch of friends are late
Teacher: "stand over there" Teacher: explains what ever were doing to the class Teacher: "why were you late?" My friend: because vijay(me) fell over and we helped him (while trying not to laugh)? Teacher: "are you ok?" Me: ... I guess.
The teacher lets us off and we are not in trouble lol, you may be thinking why it's weird well if a 16 year old comes up with some story about falling over which sounds like something a 5 year old would do the teacher would be suspicous but for some reason she fell for it (She thinks I'm a child despite my ability to balance complex equations)
A good excuse for being late to class is to say something like "My lock got flipped (if you want you can say somebody flipped in that class flipped it)" or if someone else got into the class just a bit before you you can say that that person tipped all of your books or tripped you.
I got into a punch on at a party on the weekend so I had some marks to show for it and then I just left my bag at home and said I got into a fight and bailed on my way to school.
lol those really are terrible excuses. although with one of my teachers would accept bad excuses if you used stuff that they are talking about in class and vocab words then he might let you go with just a warning!