Saying that you are too tired to get up and go to class is a bad excuse and doesn't really fly so here are some that might. Just make sure that it isn't a test day.
The Classic "I'm Sick"
GiphyA fever will make you seem like an unfocused student and they don't want that so fake a low grade fever and skip that boring bio lecture.
Doctor/Dentist Appointment
GiphyAlways a winner. You can't help that the only appointment they had open was during class but you NEED to go. Your health is 'very' important.
I have an interview
GiphyIt can be an interview for a job or an internship, you really don't need to elaborate but it is always a winner. It makes the teacher think that you are doing something productive instead of sitting around finishing your binge session on Netflix.
Organizational Commitment
GiphyI give tours on campus so I have used this excuse a few times and all of my professors are okay with it since it is for the school. Extra points to you if it is for a school sponsored org.
"I have another meeting with another professor"
GiphyThey can't be mad if you have a professor who only comes to campus on Wednesdays and only has office hours during class. If you need to talk you need to talk.
"Sorry prof, I have jury duty"
GiphyI wouldn't use this if your professor requires paperwork to prove an absence but if they don't and you want to get out of class for a few days, this is a sure winner.
An Accident
GiphyA fender bender, a big accident, whatever just make sure your lie is small enough that they won't be looking for it on the 10 o'clock news.
Claim a BIG Illness
GiphyLice, chicken pox, food poisoning, anything big enough that makes them feel like begging you to stay home.
A Medical Test
GiphyIf you are in the education program, you need to have a TB every so often so use that as an excuse. If you aren't going to be a teacher, find another minor and relevant test that you can use on your teacher.
Traffic Jam
GiphyWith the exception of freshman (and any info that you've shared), your professor has no idea that you live on or off campus. There could have been some bad traffic and it isn't your fault that you got to campus right as class ended.
Car Break In
GiphyI know there are a lot of random break ins to cars at my school so using that as an excuse and saying that you have to deal with the police is always a safe bet.
A Mental Health Moment
GiphyThis can be a lie or a valid excuse but sometimes you just need a you day and telling them that you need a mental health break is a good excuse that they can't refute.