I love the Lonely Planet guides, but I don't like the budgeting that comes with them. I'd quite like an app into which you could say "I have a budget of $THIS_M

I love the Lonely Planet guides, but I don't like the budgeting that comes with them. I'd quite like an app into which you could say "I have a budget of $THIS_MUCH, plus or minus $THAT_MUCH for the day. I am in $LOCATION and I would like to experience $THESE_SORTS_OF_FUN_THINGS. Please generate, perhaps pseudo-randomly, an itinerary of fun for the next $NUMBER of hours with all that in mind".