http://www.mathematicalresilience.org/
http://www.bowlandmaths.org.uk/
and
http://www.bowlandmaths.org.uk/assessment/index.html
Latter has example activities and sample student responses.
(I'm a happy participant, no financial interest, &c.)
http://www.mathematicalresilience.org/
http://www.bowlandmaths.org.uk/
and
http://www.bowlandmaths.org.uk/assessment/index.html
Latter has example activities and sample student responses.