I would go for common toads, they'd probably do best in captivity because common frogs would need a great deal of space because they jump a lot. They're strictly nocturnal and it's usually only babies that will be active during the day. If you wait a month or so there will be plenty of little babies and it would be better to collect and raise them to adults in captivity, they would do better. Otherwise, adults they will be out on wet nights in the woods or paths near ponds. Tanks will need set up in cool rooms or a garage as temps should be kept much below 24C. Make sure to check if this is legal and never release collected animals back into the wild.

Jason