I am semi-reguarly going to the gym (2-3x per week, depending on the week), and I decided to try a home workout challenge this week, adding 15 pushups every single week from Monday. At first I was doing sets of 15 but I've changed my style with time to minimize sets and maximize intensity.
Monday: 15
Tuesday: 15+15 (30)
Wednesday: 15+15+15 (45)
Thursday: 20+20+20 (60)
Friday: 20+20+20+15 (75)
Saturday: 20+20+15+15+10+10 (90)
Today I gotta do 105 and am considering how I want to approach it. Or, I can cap it at 100 and try to just do 100/day. Do you guys feel like it would be better to do 100/day or continue trying to increase my reps? Or perhaps I should start incorporating different pushup techniques (narrower hands, diamonds, lower hands, etc)?
I'd go with different variations. Maybe switch to something like pike pushups and do those until you can do 100 of those in a day.
C25K is a good casual cardio challenge. You'd start off with just walking and end with jogging a 5k.