There are some workouts that are memorable. Just plain guts and glory. You leave the gym with a feeling of accomplishment. Here is one of them. Time of work equals time of rest, which means you do as many reps as you can. So, if you do 30 reps and it takes you 45 seconds, you get 45 seconds of rest. Then you keep going until you reach 100 reps. For most exercises, use 60% of max weight or bodyweight for squats, pushups and pull-ups for example. Choose 5 exercises and give it a try.
Here is an example.
Bodyweight squats x100
Deadlift (barbell = bodyweight) x100
Chin ups (or lat-pulldown with bodyweight) x100
Floor sit ups x100