Speaking of climbing… oh wait, I wasn't… anyway…
with all the recent work done on UpperCut by BMBA and some recent follow-up by CoB (I believe), and the work done on GJ this winter by UniverCity, Jay Hoots, and some trail fairies, this is a pretty good alternative climbing route up the mountain.
I recommend doing this NOT during peak hours, as things have bushed in pretty good with spring foliage, so sight-lines are pretty bad and their are a lot of skidding pinners coming down GJ that don't necessarily follow the ruler about stopping for uphill traffic.
But, in the morning, riding Function Junction, up UpperCut, up Lower and Upper GJ is a really good climb. For me, with a 30t front and 40t rear, it's about 85-90% rideable. Would only take a few tweaks to make it consistently 90%.
Another option, climbing Mel's from TransCanada to Upper GJ and then climbing Upper GJ is nearly 100% rideable now, with the exception of the first two switchbacks at the bottom of Mel's. They could be rideable with some trail fairy love. The other steep pitches were all filled in and buffed out by a trail fairy a couple months ago and are holding up well, making this a very pleasant climbing route with less DH traffic at Peak hours. Upper GJ has better site-lines than Lower GJ for climbing as well if doing it during higher traffic times.
Burnaby has also buffed up Pandora's as a climbing trail only. So this is a great link-up now and a reason to actually ride Hang Your Hat, Mountain Air, and Velodrome Trail.