I have just been along to the St Nicholas Church 'Knit and Natter' group.  One of the projects they're involved with is the local Wirksworth Rotary Club's Aqua Boxes (see link below) for which the Knit and Natter group are making easy-to-knit T-shaped jumpers.   

this looks similar to the jumpers we're making

I'm going to have a go as it looks comparatively simple and apparently the best idea is to make these in fun brightly coloured stripes.  Here is the pattern:

T-shaped jumper for aqua boxes*
This is a pattern for older children

1. With 3mm (No 10) needles and double knitting wool cast on 60 stitches
2. Knit 10 rows garter stitch (all knit)
3. Change to 4mm (No 8) needles and knit 64 rows in either stocking stitch (1 row plain, 1 row purl) - or garter stitch.
4. Increase 1 stitch at each end of the next 5 alternate rows (70 stitches).
5. Cast on 25 stitches at the beginning of each of the next two rows
6. Knit 46 rows on these 120 stitches.
7. Knit 40 stitches, turn and knit two rows on these 40 stitches, cast off those stitches.
8. Rejoin the wool in the middle of the two to stitches left and cast off 40 stitches, knit to the end.
9. Knit two rows then cast off those 40 stitches.
10. Knit another piece exactly the same.
11. Sew up the side and the sleeve seams.

* see http://www.aquabox.org/