How do you get in the 300 squats? I'm curious.
It's not unusual for me to do around 200, but I do them in sets. I might do 3 sets of squats with an overhead press, and then 3 sets of squats with a tricep move and then 3 sets of squats with a bicep curl. I also like to run up and down the stairs for 3:00 and then do 20 squats. I understand about needing to increase the intensity for legs. Those 20 squats with the stairs are nothing to me now.
Rather than aim for 300, I aim for different. Squat pulses are great and I feel 20 of those more than 20 regulars. I've started squatting with a bar bell and increasing the weight as I am less scared. LOL! I'll do squats on a bosu ball with dumb bells in hand. I also work on getting lower, improving my form.
It's hard to wait for a challenge, but the day will come.
I've learned not to join too many. I've kind of stopped joining online challenges, maybe because my spin instructor offers them up every now and then and I get a real kick out of real life challenges. You're right about challenges fizzling here and it ends up being you talking to yourself. I know for me, I get frustrated when everyone's reporting what great losses they have and I tend to put in tons of effort for very little loss.