It's impossible to have a conversation about Scouts and Scouting without the word 'woggle' cropping up, and I think I heard someone say it on the radio this morning. The story was that the Scouts are bringing back 'bob-a-job week', plus an amount for inflation, presumably, since a bob was a shilling pre-decimalisation (1971), the equivalent of 5 pence (and you can't buy anything for 5p these days - using the toilets in Waterloo Station costs 30p). The new name -- Scout Community Week -- isn't quite as catchy as Bob-a-job week.
The OED doesn't know why 'bob' meant shilling. It says that bobe was a 14th-century French coin of little value, but that it is unlikely that this word subsequently became English slang. In the 19th century there was another catchy phrase - bob a nob, which meant a shilling per head or per person. There was also another slang word for shilling -- bobstick -- and bob is perhaps an abbreviation of this. However, no-one knows the origin of bobstick either.
The word woggle is of uncertain origin, too, alas. A woggle is a loop of leather to hold the Scout's scarf (see a picture on this page). The OED refers readers to the word toggle, originally a nautical pin.